vfont bitmap alignment (Re: versatec font editor)

[Don't tell me the rerun season has started already!?!?!?!]

>X-Sun-Spots-Digest: Volume 7, Issue 245, message 16 of 15
>
> ...
>
>... By the way:  there is a small but important
>difference between Berkeley's standard "vfont" format and the one that Sun
>uses:  the bitmaps for standard vfonts are byte aligned, but the bitmaps
>for Sun vfonts are *word* aligned!  --wnl

This is incorrect, the bitmaps in Sun vfont files are byte aligned
(padded).  There's an old ditroff previewer floating around which also
thinks vfonts are short padded; maybe that's what caused the confusion.
vfont(5) is pretty clear:

	The bit map contains up+down rows of data for the character, each
	of which has left+right columns (bits).  Each row is rounded up to
	a number of bytes.

If that's not convincing, let's look at a typical screen font...

% vfontinfo screen.r.7 ab
Font screen.r.7, raster size 760, max width 6, max height 6, xtend 2

           ASCII     offset    size  left    right   up     down    width 
screen.r.7  141  a      520      8      0      6      6      2       6
screen.r.7  142  b      528      8      0      6      6      2       6

The bitmap for 'a' occupies 8 bytes, therefore each scan line is 1 byte.
Q.E.D.
-- 
David DiGiacomo, Sun Microsystems, Mt. View, CA  sun!david david at sun.com

[[ Okay.  At one point they WERE word aligned, around about version 2.  I
just assumed that that was still the case.  --wnl ]]